[Recognition mechanism of hepatitis C viral infection]

In the viral reproduction, hepatitis C virus(HCV) produces double-stranded RNA (dsRNA) as a replication intermediate. RIG-I(retinoic acid inducible protein I) recognizes the intracellular HCV dsRNA as a "non self" molecule, and triggers the induction of interferon (IFN)-β and then numerous IFN-stimulated genes(ISGs). On the other hand, one of toll-like receptors, TLR3 also recognizes the extracellular HCV dsRNA, and subsequently triggers the induction of IFN-β and ISGs. We recently reported class A scavenger receptor (MSR1) was required for TLR3-mediated recognition of the extracellular HCV dsRNA. In this review, we summarize current knowledge about RIG-I- and TLR3/MSR1-mediated recognition mechanisms of HCV infection.